Re: [xml-dev] Unique values in XML documents

[Christian Nentwich <c.nentwich@cs.ucl.ac.uk>]

> I have a series of XML documents. I want to ensure that when any of these
> documents
> contains the following element:
> <id></id>
> That the value supplied is unique across all <id> elements contained in all
> the documents.

You can do this quite easily in xlinkit (see http://www.xlinkit.com) as
follows:

<forall var="x" in="//id">
  <forall var="y" in="//id">
    <implies>
      <equals op1="$x/text()" op2="$y/text()"/>
      <same op1="$x" op2="$y"/>
    </implies>
  </forall>
</forall>

Depending on how complex your constraints get, this may/may not be
inconvenient for you.

Christian